title: The tetraspanin gene MaPls1 contributes to virulence by affecting germination, appressorial function and enzymes for cuticle degradation in the entomopathogenic fungus, Metarhizium acridum.
abstract: In most eukaryotes, tetraspanins regulate cellular activities by associating with other membrane components. In phytopathogenic fungi, the tetraspanin Pls1 controls appressorium-mediated penetration. However, regulation of Pls1 and its associated signalling pathways are not clear. In this study, the MaPls1 gene from the entomopathogenic fungus Metarhizium acridum was functionally characterized. MaPls1 was highly expressed in mycelium and appressorium, and accumulated on the plasma membrane or in the cytoplasm. Compared with a wild-type strain, the deletion mutant ΔMaPls1 had delayed germination and appressorium formation and impaired turgor pressure on locust wings, but normal germination on medium and non-host insect matrices. Bioassays showed that ΔMaPls1 had decreased virulence and hyphal body formation in haemolymph when topically inoculated, but was not different from wild type when the insect cuticle was bypassed. Moreover, the ability to grow out of the cuticle was impaired in ΔMaPls1. Digital gene expression profiling revealed that genes involved in hydrolysing host cuticle and cell wall synthesis and remodelling were downregulated in ΔMaPls1. MaPls1 participated in crosstalk with signalling pathways such as the cyclic adenosine monophosphate-dependent protein kinase A and calmodulin-dependent pathways. Taken together, these results demonstrated the important roles of MaPls1 at the early stage of infection-associated development in M. acridum.
authors.affiliation: School of Life Sciences, Chongqing University, Chongqing Engineering Research Center for Fungal Insecticides and Key Lab of Functional Gene and Regulation Technology under Chongqing Municipal Education Commission, Chongqing 400030, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Luo
authors.affiliation: School of Life Sciences, Chongqing University, Chongqing Engineering Research Center for Fungal Insecticides and Key Lab of Functional Gene and Regulation Technology under Chongqing Municipal Education Commission, Chongqing, 400030, China.
authors.forename: Min
authors.initials: M
authors.lastname: He
authors.affiliation: School of Life Sciences, Chongqing University, Chongqing Engineering Research Center for Fungal Insecticides and Key Lab of Functional Gene and Regulation Technology under Chongqing Municipal Education Commission, Chongqing, 400030, China.
authors.forename: Yueqing
authors.initials: Y
authors.lastname: Cao
authors.affiliation: School of Life Sciences, Chongqing University, Chongqing Engineering Research Center for Fungal Insecticides and Key Lab of Functional Gene and Regulation Technology under Chongqing Municipal Education Commission, Chongqing, 400030, China.
authors.forename: Yuxian
authors.initials: Y
authors.lastname: Xia
mesh_terms: D000818:Animals; D001483:Base Sequence; D002147:Calmodulin / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004271:DNA, Fungal / Q000032:analysis / Q000235:genetics; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D007313:Insecta / Q000382:microbiology*; D052981:Metarhizium / Q000235:genetics* / Q000472:pathogenicity*; D025282:Mycelium / Q000378:metabolism; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000235:genetics; D059470:Tetraspanins / Q000235:genetics*; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D002147:Calmodulin; D004271:DNA, Fungal; D059470:Tetraspanins; D037521:Virulence Factors; D017868:Cyclic AMP-Dependent Protein Kinases